Automatic analyzer

Abstract

An automatic analyzer is capable of ensuring sufficient nozzle cleaning and suppressing of deterioration in the accuracy of analysis. When it is judged that there remains no analysis item of the sample, a judgment is made on whether the sample dispensation quantity of the n-th sample dispensation is less than a dispensation quantity threshold value or not, and if less, a cleaning pattern is selected by making a judgment on whether or not all the sample dispensation quantities of the first through (n−1)-th sample dispensations are less than the dispensation quantity threshold value. If the sample dispensation quantity of the n-th sample dispensation is the dispensation quantity threshold value or more, another cleaning pattern selected by making the judgment on whether or not all the sample dispensation quantities of the first through (n−1)-th sample dispensations are less than the dispensation quantity threshold value.

The invention claimed is: 
     
       1. An automatic analyzer comprising:
 a sample dispensation mechanism including a sample nozzle which sucks in a sample stored in a sample vessel and discharges the sample into a reaction vessel of a plurality of reaction vessels; 
 a reagent dispensation mechanism which sucks in a reagent stored in a reagent vessel and discharges the reagent into the reaction vessel; 
 a reaction disk holding the plurality of reaction vessels; 
 a cleaning bath, including a solenoid valve and a pump, which cleans the sample nozzle with cleaning water; 
 a photometer which analyzes the sample in the reaction vessel; and 
 a controller which controls the operation of the reaction disk, sample dispensation mechanism, the reagent dispensation mechanism, the cleaning bath and the photometer, 
 wherein the controller is programmed to: 
 control the sample dispensation mechanism to suction a sample stored in a sample vessel in a suction operation, discharge the sample into a reaction vessel in a discharge operation, control the solenoid valve to open and close and control the pump to pump cleaning water thereby cleaning the sample nozzle in a cleaning operation, wherein within repeating and consecutive operation cycles, wherein an operation cycle is a first period of time in which the reaction disk rotates by a first amount, at least one of the suction operation, discharge operation, and cleaning operation are performed within each operation cycle, 
 for a sample stored in a sample vessel, control the sample dispensation mechanism to perform N number of suction operations to suction the sample N times in different operation cycles, wherein N is an integer greater than 1, 
 determine whether a maximum sample suction quantity among the first through (N−1) suction operations performed for the sample is greater than a threshold and determine whether a sample suction quantity of the last suction operation among the N number of suction operations for the sample is greater than or equal to the threshold, 
 if the maximum sample suction quantity and the sample suction quantity of the last suction operation are less than the threshold, perform the cleaning operation of cleaning the sample nozzle once in a same operation cycle in which both the last suction operation was performed and a discharge operation of discharging the sample suctioned by the last suction operation is performed, and 
 if the sample suction quantity of the last suction operation is greater than or equal to the threshold, perform the cleaning operation of cleaning the sample nozzle at least twice in an operation cycle immediately following an operation cycle in which both the last suction operation was performed and the discharge operation of discharging the sample suctioned by the last suction operation is performed. 
 
     
     
       2. The automatic analyzer according to  claim 1 ,
 wherein if the sample suction quantity of the last suction operation of the sample is less than the threshold and the maximum sample suction quantity is greater than or equal to the threshold value, perform the cleaning operation of cleaning the sample nozzle at least twice and one of the at least two cleaning operations is performed in the same operation cycle in which the last suction operation was performed and the discharge operation of discharging the sample suctioned by the last suction operation is performed and the other of the at least two cleaning operations is performed in an operation cycle immediately following. 
 
     
     
       3. The automatic analyzer according to  claim 1 , wherein
 the cleaning bath further includes a pipetter configured to adjust the pressure of water used to clean the sample nozzle, and
 wherein the controller is further programmed to: 
 
 if all the sample suction quantities of the N number of suction operations are less than a first threshold value, control the pipetter to adjust the water pressure to a first pressure, and 
 if any of the sample suction quantities of the N number of suction operations is greater than or equal to the threshold, control the pipetter to adjust the water pressure to a second pressure higher than the first pressure. 
 
     
     
       4. The automatic analyzer according to  claim 1 , wherein
 the controller is further programmed to: 
 if any of the sample suction quantities of the N number of suction operations of the sample are greater than the first threshold and less than a second threshold control the pipetter to adjust the water pressure to the first pressure and perform the cleaning operation twice in the operation cycle subsequent to the operation cycle in which both the last suction operation was performed and the discharge operation of discharging the sample suctioned by the last suction operation is performed, and 
 if any of the sample suction quantities of the N number of suction operations of the sample are greater than or equal to the second threshold, control the pipetter to adjust the water pressure to a second pressure higher than the first pressure and perform the cleaning operation twice in the operation cycle subsequent to the operation cycle in which both the last suction operation was performed and the discharge operation of discharging the sample suctioned by the last suction operation is performed. 
 
     
     
       5. The automatic analyzer according to  claim 1 , wherein
 the controller is further programmed to: 
 if the sample suction quantity of the last suction operation is greater than or equal to the threshold and the maximum sample suction quantity is greater than the threshold, perform the cleaning operation of cleaning the sample nozzle four times and two of the four times are performed with an operation cycle immediately following the operation cycle in which both the last suction operation was performed and the discharge operation of discharging the sample suctioned by the last suction operation is performed and perform the other two of the four times in an operation cycle subsequent to the immediately following operation cycle, and 
 if the sample suction quantity of the last suction operation is greater than or equal to the threshold and the maximum sample suction quantity is less than the threshold, perform the cleaning operation of cleaning the sample nozzle only twice within an operation cycle immediately following the operation cycle in which both the last suction operation was performed and the discharge operation of discharging the sample suctioned by the last suction operation is performed.